If you were taxing your cardio vascular system maximally, I don’t think your heart would just chill at threshold HR, but decide to pump more blood per beat. Increased SV is an outcome of good VO2 max training, not really something you perceive during those intervals.
IME if you must attribute an HR value instead of maximal efforts, then exceeding 90% is a reasonable place to start.
By the end of the blocks of the type of VO2max workouts I use and prescribe, most people are barely hitting LTHR… but they’re still breathing as hard as they ever have if they’re doing it right. HR is like a tertiary metric and should really only be reviewed AFTER, IMO anyway.
It just means it felt like I was pumping a lot more per beat than usual, which is something I often feel on hard but short efforts.
Yes, they will ramp the next workout blazingly fast if you are on a plan, but otherwise it doesn’t increase the level by more than the level of the workout. So if you’re doing Train Now or self-selecting workouts, you could end up doing workouts that are too easy for a long time.
That’s what I suggest those people do a fully sweep of stretch/breakthroughs that they think they could do.
Thanks for this discussion. I’ve been having a similar issue. Despite progressions thanks to AT, it’s been feeling like my VO2 workouts have been getting easier, if anything, and my heartrate has not been getting as high as during my threshold workouts. The latest was 30/30s at 130% FTP, though short sets of 5 which I think didn’t give my heartrate enough time to go up. My threshold workouts have been appropriately tough–if anything they’ve felt too hard, though I think that’s more because I haven’t stretched enough before them and haven’t dialed in my preworkout fueling.
I’ve mostly been trusting AT, though, which has my VO2 workouts advancing much more quickly than my threshold workouts.
This is likely the adaptation of being really tired and in need of rest.
Yes I am aware of that. Just pointing out that you can do quality VO2max sets without being at XX% of any particular heart rate. Being at a high heart rate doesn’t mean you’re working VO2max necessarily. It just means you are at a high heart rate… just like putting out 125% of FTP doesn’t necessarily mean you’re working VO2max either.
I did 5 sets of 9 x 30 / 30 yesterday, 2.5 mins recovery between sets. Here’s the heart rate trace. Every set the maximum heart rate exceeds that of the previous set. From the third set onwards (set two wasn’t too far short) I’m getting above that 90% of max HR. The fifth set the chest strap dropped out briefly, not quite tight enough and it had shifted during one of my intervals. I shifted it back in the 30 second recovery. I’d agree that at 5 per set you’ll get a lower max heart rate than longer sets.
I wouldn’t knock the shorter sets though. Last week was a recovery week where I did 2 x 7 x 30 / 30. Still worth doing in my opinion. It was a slightly higher average intensity of intervals looking at numbers, but as said I just try and do what I think the legs can sustain as long as I’m not dropping too low (in which case it may be time to just end the session).
I aim for a range with them. I try and stay above a minimum intensity and if the legs feel good I’ll push it a bit more. I recently got a Garmin out front power mount, so I can no longer mount my iPad to the handlebars. I have the screen on a shelf just off to my right. I’m kind of doing these blind now, glancing across when I’ve got about 5 seconds of an interval to go. Plus a quick glance during recovery period to see when the next one is about to start. Probably do me good not to be staring at the numbers, and just putting out what I think I can sustain.
This 
Except the prescribed %FTP using ERG for the majority of users will be absolutely close enough to elicit sufficient training response. 
What is blazingly fast? I don’t use adaptive training for this purpose as i feel that if i need to intervene at all for AT to work properly, then it seems pointless to me as i already have shown i know what is appropriate for my goal. AT doesn’t remember you start at a pl of 4 or 5 which is where I’ve noticed i can start on VO2max workouts even though my career says I’m at pl 1.
Also, the forcing down of the power levels after an ftp change seems a bit too conservative so it looks like people need to pfaff around for several weeks before you get an appropriate vo2 workout.
It depends of course… but much of the power level 4 and below aren’t much of vo2 workouts as they are very short duration intervals relative to intensity and have large rest intervals.
I have very good results for 110% power target, but that might then be 6x4 minutes with 4 min recovery. I thought i had that one starred as a favorite but will have to look at my calendar to see its name.
I’m comfortable saying I personally was leaving something on the table doing TR VO2 Max workouts in erg mode as prescribed and just riding the power target at whatever cadence felt most comfortable. I spent a year on a TR LV plan, doing all my workouts as prescribed on the trainer, all in erg mode. VO2 Max workouts would get “Hard” but, not really.
I am now finishing my first block of VO2 Max workouts the way @kurt.braeckel prescribes them, #9 in 3 weeks coming up tomorrow, and it’s a different world in terms of difficulty and primarily how hard I’m breathing and overall RPE finishing every interval.
Looking at metrics in TrainingPeaks and WKO, EF has been going up consistently throughout the block, and not that the Garmin VO2 Max number is “accurate” but I’ve watched it trend up over the last 3 weeks and hit the highest number I’ve ever hit. So, I don’t think this is all subjective either. I am adding more Z2 right now than I ever have in the past, but I’m not attributing 3-4 weeks of that as what’s making the difference.
YMMV, but I’d encourage everyone to give changing up the method of HOW you ride your VO2 Max workouts a try like @kurt.braeckel and @WindWarrior are mentioning. Turn off Erg for the VO2 intervals. Spin it to win it - 110-115 cadence or more. Mine hits 130+ for hard starts and drifts down to 110-115. Target max repeatable power but really get your breathing rate as high as possible and hold on, if power has to drift down throughout the interval or intervals - then fine. I’m also not holding myself religiously to the rest interval, when I’m recovered, then I GO and go hard and give that interval everything I have.
Relative newbie perspective but even though I’m still a TR subscriber, been valuable for me working with a coach here. Always something new to learn…
With the caveat… max repeatable power while leaving 1, maybe 2 reps in the tank. With that said though… if i go by rpe, my power will drop after the first two and then get more consistent.
But, not everyone follows this guideline. If it is week one of a 4 week block, i definitely don’t want to do the max repeatable power. That is what’s in store for the last week.
Yeah I don’t ever prescribe 30/30s as VO2max work. If anything, I’ll give them very early season to train an anaerobic component and prep the body for VO2max work… or I give them as ALL OUT - recover - anaerobic repeat sessions where you do like 5x30/30 and do 2-4 sets for crit racers.
I just don’t think 30/30s are going to elicit much time spent at VO2max. 30/15s? I do give those for MAP workouts, and they’re more effective in that regard. But pure VO2max I see most people I’ve done this with get the most benefit from the longer intervals 3-6min and 15-25min TiZ.
I’ve said this before on this forum re: VO2max… we overuse that term in endurance sports.
Training at XXX% of FTP does NOT necessarily mean you’re training VO2max.
Training at YY% of HR does NOT necessarily mean you’re training VO2max.
Using “VO2max” to describe power or HR zones is a mistake, but we’ve done it…
You train VO2max by getting to maximal O2 uptake and staying there. That’s generally done by achieving the hardest breathing you’ve ever done in your life and sustaining that for as much time as you reasonably can. Unless your body is DEMANDING more O2 in every possible way - blood flow/HR, maximal air intake… you’re probably not training VO2max.
You can train Max Aerobic Power, and that training is similar to VO2max training and you might hit VO2max while training it. (This is stuff like 30/15s holding high power for more maximal time than you can in a straight shot; or just doing max power for like 5 min without regard to cadence, HR, breathing, etc.).
You can train anaerobic repeatability… and you might even hit VO2max for a little bit when doing that. (Hit the highest possible power that you can over and over again for 30s on 30s rest, e.g.)
But again, we’re overusing VO2max as athletes, coaches, etc. I’ve coached three people coming off of TR plans, two coming of Zwift plans, a couple coming off of things from other coaching companies, and I don’t think any of them have really trained VO2max before. I know that because of their subjective feedback and then (so far) on the immediate gains they see after the blocks. In my experience, albeit somewhat limited compared to some longer-tenured coaches out there, I do believe that most athletes with at least some training history are limited by VO2max. It’s rare so far (I think probably 2 of my current 12 athletes) that I take on someone who just gets a lot of gains right away from doing FTP/SST work. Seems like they come to me when that’s all tapped out. 
Just here to say you can’t feel stroke volume of your heart… just like you can’t feel blood pressure. You say you felt strong… which is good… but it is likely due to some other stimulus.
Just because this is a message board and we get to nitpick… but won’t hr also respond in the same way as respiratory rate?
It doesnt matter how hard your breathing if your blood isnt also carrying near the max capacity for one to be at a specified max. The two responses are dependent on the other to reach vo2max.
So while there’s a definite hr lag in high intensity intervals, tracking % of max is a valid metric.
Can we just make this post a sticky on the forum - there must be one of these type of posts per week…
@kurt.braeckel speaking truth bombs every time.
Above FTP - turn off ERG, go max for the time alotted, get faster.
Not always. When I do anaerobic work, for example, HR will get high but breathing never approaches max. Long threshold work, I can drive my HR to 177 (max of 187) and I’m not breathing anywhere near as hard. Conversely, I can do a VO2max set where HR might get up to 180, but by my 13th set of a block, I’m hitting mid-160s but still breathing as hard as I can, still generating the same power, still spinning at 110rpm.
While a lot of different work will help maintain VO2max because it’s aerobic, if you’re actually looking to make improvements in VO2max, that’s where you need to be providing a stimulus of maximal O2 demand without overreliance on sugar. This is where the focus on a high cadence, a longer interval time come into play. You’re trying to stimulate maximal blood return from your legs by forcing more (smaller) contractions by spinning at a high rate. This will force your heart to move more blood, yes, but doesn’t always drive HR up maximally as you fatigue throughout the block… but you can still stimulate maximal O2 uptake through breathing rate, etc. Don’t forget too that one of the adaptations you’re looking for when training VO2max is improved stroke VOLUME, not necessarily stroke rate. Part of seeing HR go down through a block is fatigue, but if you see coincident power increase or stabilization, you know what you’re doing is working acutely… then eventually the wheels fall off and EF/power and HR all trend downwards (or CNS fatigue hits in a big way) and it’s time to pull the plug.
So when I program these, I tell my athletes to focus on cadence primarily, power secondarily, breathing. I look at HR after the fact… having them sit and try to hit a certain % of HR is often going to be an exercise in futility… they might not be able to, or conversely, they might do it and limit themselves to that HR unnecessarily depending on fitness/freshness.
So yes, I’d agree that you need a relatively high HR and a high breathing rate to be working VO2max. High HR or XX% of HR is not enough because there are a billion ways to get there.
Remember too that when you’re focusing on training one thing, you’re also training other things. There’s no magic button to push that says “NOW you’re training VO2max… OH! NOW you’re training threshold.”
There are just different ways to create a stimulus that focuses on certain things more than others. If you wanna train VO2max, you want maximal breathing (and necessarily high HR). If you wanna train Max Aerobic Power, you need to be doing high power. But doing VO2max work will elicit some gains in MAP; training MAP will (sometimes) stimulate gains in VO2max.
I don’t think that has much to do with warming up or not. I just think that’s people not knowing how to pace themselves, and I’m not really sure it’s a great example. I’ve run for three decades and never experienced going out and running at a sub-threshold pace getting me anywhere close to VO2max style breathing. n=1 for sure, but I can’t relate to this.
No one is advocating using “breathing alone”. I’m advocating using “breathing primarily”. But do I care if someone gets their HR up to 88% or 95% of max doing VO2max work? Not really, no. If they’re doing it right, HR will necessarily be high… but as I mentioned, you can drive your HR up without achieving max O2 uptake because a large part of the reason we breathe and elevate HR is to remove metabolic byproducts (CO2), not just to intake/uptake O2.
